Dry shaver cutting head

ABSTRACT

A dry shaver having a pair of reciprocating cutters, with a flexible arcuate shear plate formed as a partial cylinder for each cutter, the plates having two adjacent, parallel edges, and two outer, parallel edges, the latter engaging and being restrained by the corresponding edges of a shaving head housing.

[ 3,765,086 Oct. 16, 1973 United States Patent [191 Zuurveen 7 DRY SHAVER CUTTING HEAD FOREIGN PATENTS on APPLICATIONS 353,652 5/1961 Switzerland........................ 30/4392 [75] Inventor: Frans Zuu'rveen, Briarcliff Manor,

N.Y. Assignee: U.S. Philips Corporation, New

Primary Examiner-Othell M. Simpson Attorney-Frank R. Trifari York, N.Y.

Feb. 4, 1971 [22] Filed:

211 App]. No.: 112,798

ABSTRACT Related U.S. Application Data [60] Division of Ser. No. 859,247, Sept. 17, 1969, Pat.

No. 3,639,979, which is a continuation of Ser. No. 670,506, Sept. 6, 1967, abandoned.

A dry shaver having a pair of reciprocating cutters, with a flexible arcuate shear plate formed as a partial cylinder for each cutter, the plates having two adjacent, parallel edges, and two outer, parallel edges, the latter engaging and being restrained by the corresponding edges of a shaving head housing.

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3 Claims, 4 Drawing Figures [56] References Cited UNITED STATES PATENTS 2,841,867 7/1958 Padgett.......................... 30/4392 X Patented Oct. 16, 1973 2 Sheets-Sheet ll FIG.3

Patented Oct. 16,1973

2 Sheets-Sheet 2 DRY SHAVER CUTTING HEAD CROSS REFERENCE This is a division of US. Pat. No. 3,639,979, issued Feb. 8, 1972 having Serial No. 859,247, filed Sept. 17, 1969, which is a continuation of abandoned appln. Ser. No. 670,506, filed Sept. 6, 1967, priority being claimed under corresponding Dutch application Ser. No. 6,613,222, filed Sept. 20, 1966.

The invention relates to dry-shaving apparatus and firstly to a dry-shaving apparatus as described in a prior Patent application Ser. No. 665,850, filed Sept. 6, 1967, now abandoned in favor of continuation, Ser. No. 849,553, filed July 18, 1969 of the kind including a thin elastic arcuate shear plate which is provided with hair-inlet apertures and the shaving surface of which is in the form of a surface obtained by rotation about an axis of a curved line portion not intersected by the axis of rotation so, that the shaving surface forms part of a toroidal surface, the shear plate having acircular outer edge and a circular inner edge concentrical thereto, while a movable cutting member adapted to rotate or to oscillate in operative below said shear plate, the cutting member and the shear plate being pressed against each other, and secondly to a dry-shavingapparatus of the known type including two thinelastic arcuate shear plates which are provided with hair-inletlapertures and the shaving surface of which is in theform of'a surface constituted by two parallel'lines which each intersect one of two curved line portionsnot intersecting each other, lying in one flatplane and'not containing these parallel lines, so that the shaving surface forms part of the surface of the two parallel cylinders, two parallel straight outer edges and two inner edges extending parallel thereto, a movable cutting member adapted to perform a reciprocating movement being operative below said shear plates and the cutting member and the shear plates being pressedadainst each other.

The two types of dry-shaving apparatus are referred to hereinafter for the sake of simplicity as dry-shaving apparatus having a toroidal shaving head and dryshaving apparatus having a double cylindrical shaving head.

ln'the case of the toroidal shaving head, the thin elastic shear plate is streched over a likewise. toroidal cutting member adapted l to rotate or to oscillate. The shear plate, which is preferably flat inthe non-streched condition, has a circular outer edge and a concentrical inner edge. With orwithoutthe use of separate resilient members, it is ensured that the cutting member and the shear plate are pressed against eachother when the dry-shaving apparatus is in the mounted state. The force thus exerted on the shear plate must ultimately be transmitted again to the housingof the dry-shaving apparatus, so that the means for securingthe shear plate to the housing must be able to transmit the required reaction force. This involves structural problems especially for the inner edge of a toroidal :shaving head below which a rotating or oscillating cutting member is operative; for a fixed part of the housing of the dryshavingv apparatus must belocated beneath the shear plate at the area of the axis of rotation, since connections on the .upper side of the shear plate are naturally undesirable so that the cutting member cannot be driven by means of a shaft which is directly coupled with the cuttingmember and the axis of rotation of which coincides with the axis of the tore.

In the case of the double cylindrical shaving-head a similar problem is involved in securing the two parallel inner edges to the housing if there are not provided two separate cutting members.

The invention has for an object to provide a dryshaving apparatus of the constructions described in which a joint between the housing of the dry-shaving apparatus and the inner edge in the case of the toroidal shaving head or the inner edges in the case of the double cylindrical shaving head can be dispensed with.

According to the invention, in a dry-shaving apparatus of the kind having a toroidal shaving head, the inner edge of the shear plate is fitted in a ring or a disc which is solely connected to the shear plate.

Also according to the invention, in a dry-shaving apparatus of the kind having a double cylindrical shaving head, the two inner edges are together fit-ted'in a strip or a rod which is solely connected to the shear plates.

In one embodiment of the invention, in a dry-shaving apparatus having a toroidal shaving head, the inner edge of the shear plate is fitted in a ring or a disc which consists wholly or in part of a synthetic material. When the shear plate is shaped into the required toroidal form ina jig with a die both having a suitable shape and the inner edge is then cast or pressed, if desired, with the use of the separate ring and/or other separate components which may consist of metal into a synthetic material, the inner edge can be fitted in a ring or a disc by a'method which is simple from a technical viewpoint.

In another embodiment according to the invention of a dry-shaving apparatus having a toroidal shaving head, the outer edge of the shear plate is also fitted in an outer ring. This affords the advantage that the inner ring or disc, the shear plate and the outer ring are integral and this assembly can be mounted on the dryshaving apparatus. When the outer ring in which the outer edge is fitted is secured to the housing of the dryshaving apparatus so that the assemby is looked against displacement in the direction of rotation of the shear cutter, the torque exerted on the shear plate due to the friction between cutting member and shear plate can be transmitted to the housing via this ring.

According to another feature of the dry-shavingap paratus having a toroidal shaving head, the outer ring ted in an outer ring by the method which has already been described for the inner edge; preferably, the inner ring or disc and the outer ring are cast or pressed in one operation.

In an embodiment of a dry-shaving apparatus having a double cylindrical shaving head, the strip or rod consists, wholly or in part, of a synthetic materialfThe strip or rod is provided in quite the same manner as already described for the inner ring or disc and the outer ring in the case of a toroidal shaving head.

In another embodiment of a dry-shaving apparatus having a double cylindrical shaving head, the outer edges are also fitted in a frame. This affords the advantage that'the shaving head forms a unit.

According to another feature of a dry-shaving apparatus having a double cylindrical shaving head, the frame consists, wholly or in part, of a synthetic material.

The invention will be further described in the reference to the drawings, wherein:

FIG. 1 is a persepctive view of a spring element for explaining a principle underlying this invention.

FIG. 2 is a perspective view of a double spring, similar to FIG. 1.

FIG. 3, is a partial elevation view in section of a new shaving head.

FIG. 4 is a perspective view, partly in section of a dry shaver of the new invention.

FIG. 1 shows diagrammatically a strip 1 having a constant cross-section and a constant width which may be made, for example, of steel and which is arranged with sliding fit at 2, while an external torque is erected on said strip at 4. The strip is loaded by a mass of material 3 which on its lower side has a shape such that it is in contact with the strip 1 at all points, If the strip is cast or secured so to say, at 4 into a block of mateiral 5 having a negligible weight and if the assembly is constructed so as to be symmetrical, the situation of FIG. 2 arises in which it is important for the block 5 to be in equilibrium without the necessity of exerting external forces on it. It is not essential that the strip should have a uniform thickness and width.

FIG. 4 shows diagrammatically a dry-shaving apparatus having a double cylindrical shaving head, the inner edges being fitted in a strip and the outer edges in a frame 21.

I claim:

1. In a dry shaver including a housing with upper side edges, a cutter which has a cutting surface and is mounted in said housing, and means for reciprocating said cutter and for biasing same outward, the improvement in combination thereiwth of a shaving head comprising a pair of flexible arcuate shear plates formed as partial cylinders and disposed in parallel with two adjacent inner edges and two outer edges, each plate having a plurality of hair receiving apertures and a cutting surface in pressure contact with the cutting surfaces of said cutters, and a strip having two sides, the strip being in contact only with the shear plates by engagement of its sides to said inner edges of said plates, the outer edges of said plates engaging said upper side eges of said housing where saidouter edges are restrained from further outward movement.

2. Apparatus according to claim 1 wherein said strip is a synthetic material.

3. Apparatus according to claim '1 wherein each shear plate has its two edges loaded primarily in bending in contrast to tension. 

1. In a dry shaver including a housing with upper side edges, a cutter which has a cutting surface and is mounted in said housing, and means for reciprocating said cutter and for biasing same outward, the improvement in combination thereiwth of a shaving head comprising a pair of flexible arcuate shear plates formed as partial cylinders and disposed in parallel with two adjacent inner edges and two outer edges, each plate having a plurality of hair receiving apertures and a cutting surface in pressure contact with the cutting surfaces of said cutters, and a strip having two sides, the strip being in contact only with the shear plates by engagement of its sides to said inner edges of said plates, the outer edges of said plates engaging said upper side eges of said housing where said outer edges are restrained from further outward movement.
 2. Apparatus according to claim 1 wherein said strip is a synthetic material.
 3. Apparatus according to claim 1 wherein each shear plate has its two edges loaded primarily in bending in contrast to tension. 